Coffee causes stress

Caffeine helps with chronic stress

Constantly stress? Then drinking more coffee could help. Because caffeine not only wakes you up, it also counteracts the typical effects of stress such as anxiety, depression or memory problems, as a study with mice suggests. According to this, the caffeine blocks a docking point in the brain that causes these stress symptoms via a whole cascade of reactions. This finding could also open up new approaches for stress therapy in humans, the researchers report in the specialist journal “Proceedings of the National Academy of Sciences”.

It is well known that chronic stress makes you sick: Anyone who is constantly annoyed with colleagues, is often disturbed in their sleep or is given one short-term deadline after the other by the boss is under constant stress. And that has consequences: Chronic stress reduces the ability to concentrate, promotes depression and anxiety and can lead to burnout.

Interestingly, most people drink more coffee in stressful situations. The popular stimulant not only wakes you up and strengthens the memory, the caffeine could also reduce the typical stress effects - at least the suspected Manuella Kaster from the University of Coimbra in Portugal and her colleagues. They have now investigated whether this is really the case.

Less stress symptoms after caffeine

In their study, the researchers administered caffeine to mice with their drinking water for six weeks at a dose of one gram per liter. During this time, they repeatedly exposed these mice and a control group without caffeine to severe stress: the animals had to swim in a pool, cross an exposed maze and were lifted up by the tail.

The consequences of this constant stress were clearly visible in the control animals: They lost weight, did worse in memory tests than before, sat around in the cage without participation and their immune system reacted weaker. The mice that received caffeine were different: Their stress symptoms were significantly weaker, as the researchers report. They were less anxious, performed better in the memory tests and also showed a normalization of the messenger substances and brain cells in the brain metabolism.

Behind this is a receptor in the brain

Behind this stress-protecting effect of caffeine is a special docking point in the brain, the adenosine receptor A2A. As the researchers found, this receptor is upregulated during stress and this triggers a cascade of reactions that ultimately causes the stress symptoms. The caffeine, however, docks to this receptor and thereby blocks this stress cascade.

"If the gene that codes for the A2A receptor was muted in the mice, or if the receptor was blocked by caffeine or specific A2A inhibitors, then the symptoms subsided due to the persistent stress," reports co-author Christa Müller from the University of Bonn.

Caffeine Therapy For Stress?

According to the researchers, the effects of caffeine in humans are likely to be similar. The coffee ingredient could therefore be a very promising starting point for stress therapies. Many people have already used this caffeine effect intuitively for a long time: "Experience shows that those who are under stress usually drink more coffee or tea," says Müller. "Because both drinks contain caffeine, this is something like self-treatment for those affected."

However, especially in higher doses, caffeine also has undesirable side effects: It keeps you awake and can lead to high blood pressure in some people. The researchers therefore developed and tested an active ingredient that, like caffeine, attaches itself to the A2A receptor. "The substance is very similar to caffeine, but has fewer side effects," reports Müller. "It only blocks the A2A receptors and has a much stronger effect than the caffeine."

Further studies must now show whether this substance is suitable for treating stress and the consequences of stress in humans. (Proceedings of the National Academy of Sciences (PNAS), 2015; doi: 10.1073 / pnas.1423088112)

(Rheinische Friedrich-Wilhelms-Universität Bonn / PNAS, 09.06.2015 - NPO)

June 9, 2015